1. Technical Field
The present disclosure relates to a printed circuit board.
2. Description of Related Art
Nowadays, many printed circuit boards (PCBs) include differential signal lines arranged in signal layers of the printed circuit boards for connection to other components. For example, a common universal serial bus (USB) interface includes two data pins which are respectively and electrically connected to a pair of differential signal lines.
Referring to FIG. 1, a conventional PCB 100 includes a signal layer 110, a dielectric layer 120, and a reference layer 130. The signal layer 110 includes a pair of differential signal lines 112 and 114. The electric fields generated by the pair of differential signal lines 112 and 114 are not perpendicular to the reference layer 130 (see arrow area in the dielectric layer 120). If the reference layer 130 has some noise therein, the noise may easily be transferred to the pair of differential signal lines 112 and 114 through channels of the electric field, which may influence transmission quality of the pair of differential signal lines 112 and 114.